FIG. 1 is a schematic arrangement diagram showing an example of a conventional photoelectric converting apparatus.
In the diagram, readout signals from photo sensors S.sub.1 to S.sub.n are accumulated in accumulating capacitors C.sub.1 to C.sub.n. When transistors Q.sub.h1 to Q.sub.hn are sequentially turned on in accordance with an operating timing of a scan circuit 101, the readout signals are successively transmitted onto an output line 102 and are output to the outside through an amplifier 103.
However, such a conventional apparatus has the problem that unnecessary components such as dark signals, drive noises, and the like of the photo sensors are included in the readout signal and the readout signal is output in this state. The drive noises are the noises which are generated when the signals are read out by driving the photo sensors. The drive noises denote the noises which are caused due to a variation in the shape of the device or the like upon manufacturing and the smears or the like which depend on an amount of light irradiation due to the separation of the device or the like.
On the other hand, the dark signal denotes the dark current of the photo sensor. A variation in the dark signal largely depends on the accumulating time of the photo sensor and the temperature.
Those unnecessary signals such as drive noises, dark signals, and the like cause a problem particularly when an image is picked up under the condition of a low illuminance. In the low-illuminance image pickup mode, the information signal level by the image pickup operation decreases, so that the S/N ratio is eventually reduced and the picture quality deteriorates. Therefore, in order to improve the picture quality, those unnecessary signals need to be reduced.
However, as mentioned above, since the dark signals largely depend on the temperature and accumulating time, and the drive noises hardly depend on them, in order to remove these unnecessary signals, it is necessary to separate both of these signals and to independently determine correction coefficients there for. For this purpose, a number of memories are needed. Consequently, signal processing is complicated, costs are increased, and the size of the image pickup apparatus increases.